Vaccine capable of inducing formation of antibodies directed to proprotein convertase subtilisin/kexin type 9 (PCSK9) in vivo

ABSTRACT

The present invention relates to a vaccine capable to induce the formation of antibodies directed to PCSK9 in vivo.

The present invention relates to a vaccine capable to induce the formation of antibodies directed to PCSK9 in vivo.

The present invention relates to novel peptides which are able to influence the Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9)-mediated degradation of the Low Density Lipoprotein (LDL) receptor (LDLR). The peptides are coupled to an immunogenic carrier and formulated to a vaccine for the prevention and/or treatment of PCSK9-related health disorders caused by hyperlipidemia, hypercholesterolemia, or atherosclerosis.

One of the major leading causes of death worldwide is cardiovascular disease (CVD). Factors such as hyperlipidemia, hypercholesterolemia, hypertension and atherosclerosis are linked to those diseases. In comprehensive epidemiologic studies, a positive correlation between the level of the serum cholesterol and the occurrence of CVD could be demonstrated. High LDL cholesterol (LDLc) levels constitute a high cardiovascular risk, and are directly correlating with increased risk for atherosclerosis.

The LDLR, mainly hepatic LDLR, is the primary pathway for removal of LDLc from plasma. Circulating LDLc binds to the LDLR and the formed complex is internalized by clathrin-mediated endocytosis. Subsequently, while LDLc is proceeded for degradation, the LDLR is recycled back to the cell surface.

PCSK9 is a secreted serine protease that binds to and promotes degradation of the LDLR. It was discovered in 2003 as the third gene locus associated with autosomal dominant hypercholesterolemia (ADH). “Gain of function mutations” (GOF) of PCSK9 enhance its interaction with the LDLR and result in a decrease of LDLR levels and markedly higher LDLc levels. Consequently, GOF are associated with hypercholesterolemia and predisposition to atherosclerosis. Conversely, “Loss of function mutations” (LOF) lead to increased LDLR levels and dramatically reduced LDLc with a subsequent reduction of the risk for coronary heart disease (CHD). Human PCSK9 is mainly expressed in liver, intestine, and kidney. It is synthesized as a ˜72 kDa protein which undergoes autocatalytic cleavage before it is secreted as a ˜65 kDa mature protein.

Circulating PCSK9 binds specifically to the EGF-A domain of LDLR. The complex is internalized by endocytosis, and instead of recycling of the LDLR back to the cell surface, LDLR is consequently degraded in the lysosomes. The net effect of the PCSK9-LDLR interaction is the reduction of LDLR available for clearance of LDLc from plasma, indicating the importance of PCSK9 as a regulator of LDLR and thus LDLc metabolism.

Several animal studies substantiate the essential role of PCSK9 as a regulator of LDLc levels. Adenoviral overexpression of PCSK9 in mice led to a significant increase of circulating LDLc. In contrast, PCSK9−/− mice show a 2.8 fold increase in the levels of LDLR and a reduction of LDLc to ˜50% compared to wild type animals. GOF and LOF mutations indicate the important role of PCSK9 in regulating LDL metabolism in humans, making PCSK9 an attractive target for pharmaceutical intervention. Notably, humans heterozygous for LOF mutations in PCSK9 seem to be healthy and have a normal life-span. Moreover, a compound heterozygote with two inactivating mutations in PCSK9 and no circulating PCSK9 has been reported to be a healthy 31-year-old African-American mother with very low levels of LDLc (14-34 mg/dl).

Several compounds reducing the amount of circulating PCSK9 or inhibiting its interaction with the LDLR were successfully tested pre-clinically and clinically (such as monoclonal antibodies, antisense-oligonucleotides or inhibitors of autocatalysis). Although PCSK9 acts intracellularly and extracellularly on LDLR, targeting circulating PCSK9 is a valuable approach for LDLc lowering therapeutics. Parabiosis experiments in mice as well as administration of recombinant protein have indicated that extracellular PCSK9 is sufficient to reduce the number of hepatic LDLR. More importantly, results from human clinical studies with PCSK9-specific monoclonal antibodies (mAbs) indicate that targeting PCSK9 enables efficient and safe reduction of LDLc. In addition, several clinical trials to evaluate the safety and efficacy of targeting PCSK9 were recently successfully finalized.

WO 2012/059573 A1 and WO 2011/027257 A2 disclose fragments of the PCSK9 polypeptide as vaccines. Li et al. (Rec. Pat. DNA & Gene Seq. 3 (2009), 201-212) and Wierzbicki et al. (Exp. Op. Invest. Drugs 21 (2012), 667-676) report about recent developments regarding inhibition of PCSK9 for the treatment of hyperlipidaemia.

In summary, PCSK9 is a major regulator of LDLR, and thus LDLc levels. Although statins represent the first line of intervention for cholesterol management, statins are not sufficient or appropriate in certain subjects to achieve the goals. Moreover, PCSK9 was found to be upregulated by statins, counteracting their pharmacologic effect. Accordingly, the identification of additional or alternative medications to control LDLc levels is of great importance. Inhibition of PCSK9 is expected to lower plasma LDLc as monotherapy, but also to augment the cholesterol lowering effect of statins or other substances (such as for example fibrates or nicotinic acid).

An object of the present invention is to provide means and methods for reducing LDLc in an individual. This object can be achieved by providing peptides which mimic the respective native sequence, so-called mimotopes. Such mimotopes are able to induce antibodies that specifically bind to human PCSK9 and inhibit the PCSK9-mediated degradation of LDLR.

Therefore the present invention relates to a vaccine, vaccine composition or composition comprising at least one peptide consisting of 9 to 25 amino acid residues having the amino acid sequence

(SEQ ID No. 1) X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m)(X₉)_(n), wherein

X₁ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of serine, threonine, valine and alanine,

X₂ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group of isoleucine, valine, glycine, glutamine and alanine, more preferably isoleucine, valine, glutamine and alanine.

X₃ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, threonine, alanine and valine, more preferably proline,

X₄ is an amino acid residue selected from the group consisting of asparagine, serine, alanine, glutamine and aspartic acid,

X₅ is an amino acid residue selected from the group consisting of leucine, glycine, alanine, tyrosine, aspartic acid, phenylalanine and valine, preferably leucine,

X₆ is an amino acid residue selected from the group of hydrophilic, negatively charged amino acid residue, preferably an amino acid residue selected from the group consisting of glutamic acid and aspartic acid,

X₇ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of isoleucine, leucine, alanine and threonine,

X₈ is an amino acid residue selected from the group of uncharged amino acid residues selected from the group consisting of threonine, leucine, glutamine, alanine and serine,

X₉ is X₁₀X₁₁X₁₂ or a C-terminal truncated fragment thereof consisting of 1 or 2 amino acid residues,

X₁₀ is any amino acid residue, preferably an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, alanine and serine,

X₁₁ is any amino acid residue, preferably an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, alanine, valine, threonine and asparagine,

X₁₂ is any amino acid residue, preferably an amino acid residue selected from the group consisting of arginine, alanine, lysine, serine, and leucine,

m is 0 or 1,

n is 0 or 1, and

SEQ ID No. 1 is not SIPWNLERITPPR or a C-terminal truncated fragment thereof,

wherein said at least one peptide is coupled or fused to a pharmaceutically acceptable carrier.

The vaccination of individuals with the peptides of the present invention leads to the production of polyclonal antibodies which bind to PCSK9. Such antibodies are able to compete with the LDLR binding. As a consequence, hepatic LDLR levels are increased and plasma LDLc and total cholesterol is decreased. Therefore, the administration of a vaccine according to the present invention allows treating or preventing diseases caused by hyperlipidemia, hypercholesterolemia and/or atherosclerosis.

The peptides of the present invention are so-called mimotopes. Mimotopes have an amino acid sequence which is different from the original protein/peptide sequence from which they are derived. Those mimotopes are considered as foreign by the immune system and therefore do not need to break self-tolerance.

The peptides of the present invention are variants (amino acid exchanges and optional truncations) of the PCSK9 fragment having amino acid sequence SIPWNLERITPPR (SEQ ID No. 2) and consist of 9 to 25 amino acid residues, preferably of 9 to 24, 9 to 23, 9 to 22, 9 to 21, 9 to 20, 9 to 19, 9 to 18, 9 to 17, 9 to 16, 9 to 15, 9 to 14, 9 to 13, 9 to 12, 9 to 11, 9 to 10 or 9 amino acid residues, more preferably of 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24 or 25 amino acid residues. It turned surprisingly out that a modification (e.g. mutation) of the tryptophan residue at position 4 of SEQ ID No. 2 and the arginine residue at position 8 of SEQ ID No. 2 results in the formation of antibodies which cannot bind sufficiently to PCKS9. The novel peptide sequences according to the present invention (especially if coupled to an immunogenic carrier and/or formulated as vaccines) are able to induce the formation of antibodies directed to PCSK9 and therefore beneficially modifying the PCSK9-mediated LDLR degradation and thus subsequently reduce plasma LDLc levels. The peptides defined with the present invention also achieve surprisingly superior results in reducing the levels of total cholesterol compared to the native PCSK9 sequences, even compared to the ones disclosed in WO 2012/059573 A1 and WO 2011/027257 A2. This is further shown in the example section of the present application by using a representative animal model. It is therefore specifically preferred to provide the peptide according to SEQ ID No. 1 with a length of 9 to 13 amino acid residues (i.e. wherein no X₁₂ is present and wherein m=1; or wherein m=0 and X₁₀ is proline, alanine and serine, and X₁₁ is proline, alanine, valine, threonine and asparagine and X₁₂ is arginine, alanine, lysine, serine and leucine).

Since the present invention is drawn to specific variants of the PCSK9 fragment having amino acid sequence SIPWNLERITPPR (SEQ ID No. 2), this original sequence and all its C-terminally truncated fragments are excluded by definition according to SEQ.ID No. 1 of the present invention. This makes clear that the original sequence SIPWNLERITPPR or C-terminally fragmented versions thereof, such as the peptides with the amino acid sequences SIPWNLERITPP, SIPWNLERITP, SIPWNLERIT, or SIPWNLERI (all derived from SEQ ID No. 2 by C-terminal deletion of amino acid(s)), are excluded from the definition of the peptide according to SEQ.ID No. 1 of the present invention in all their forms. Accordingly, it is also clear that these C-terminally truncated peptides are excluded as native peptides, as peptides coupled to a substrate with or without a linker, as peptides with a linker, such as a chemical linker or a Cys-linker, etc., especially, of course, if such peptides are provided as a vaccine.

The vaccine of the present invention may comprise at least one, at least 2, at least 3, at least 4, at least 5 or at least 10 peptides having amino acid sequence SEQ ID No. 1 as defined herein. Thus the vaccine may comprise a combination of two or more peptides as disclosed herein. However, it is also possible that the vaccine of the present invention comprises next to one or more peptides according to SEQ ID No. 1 and as defined herein also other peptides such as mimotopes (i.e. mutants of PCSK9 fragments) or fragments of PCSK9 (see e.g. WO 2011/027257). Particularly preferred fragments of PCSK9 are fragments of SIPWNLERITPPRYRADEYQPPDGGSLVEV, in particular SIPWNLERIT, SIPWNLERI, SIPWNLERITPPR, SIPWNLERITPP or SIPWNLERITP.

The peptides of the present invention can be chemically synthesized by methods which are well known in the art. Of course it is also possible to produce the peptides of the present invention using recombinant methods. The peptides can be produced in microorganisms such as bacteria, yeast or fungi, in eukaryotic cells such as mammalian or insect cells, or in a recombinant virus vector such as adenovirus, poxvirus, herpes virus, Simliki forest virus, baculovirus, bacteriophage, sindbis virus or Sendai virus. Suitable bacteria for producing the peptides include E. coli, B. subtilis or any other bacterium that is capable of expressing such peptides. Suitable yeast cells for expressing the peptides of the present invention include Saccharomyces cerevisiae, Schizosaccharomyces pombe, Candida, Pichia pastoris or any other yeast capable of expressing peptides. Corresponding means and methods are well known in the art. Also methods for isolating and purifying recombinantly produced peptides are well known in the art and include e.g. gel filtration, affinity chromatography, ion exchange chromatography etc.

To facilitate isolation of the peptides of the present invention, fusion polypeptides may be made wherein the peptides are translationally fused (covalently linked) to a heterologous polypeptide which enables isolation by affinity chromatography. Typical heterologous polypeptides are His-Tag (e.g. His6; 6 histidine residues), GST-Tag (Glutathione-S-transferase) etc. The fusion polypeptide facilitates not only the purification of the peptides but can also prevent the degradation of the peptides during the purification steps. If it is desired to remove the heterologous polypeptide after purification the fusion polypeptide may comprise a cleavage site at the junction between the peptide and the heterologous polypeptide. The cleavage site may consist of an amino acid sequence that is cleaved with an enzyme specific for the amino acid sequence at the site (e.g. proteases).

The vaccine and peptides of the present invention can be administered to any kind of mammal including humans. It is however preferred to administer the vaccine and peptides of the present invention to humans.

According to a preferred embodiment of the present invention X₁ is valine, serine, threonine or alanine, preferably valine.

According to a further preferred embodiment of the present invention X₂ is valine, alanine, isoleucine or glutamine, preferably valine.

According to a preferred embodiment of the present invention X₃ is proline, threonine, alanine or valine.

X₄ of SEQ ID No. 1 is preferably serine or asparagine, preferably serine.

According to a preferred embodiment of the present invention X₆ is glutamic acid.

X₇ is preferably leucine, isoleucine or threonine, preferably threonine.

X₈ is preferably glutamine, threonine or leucine.

According to a preferred embodiment of the present invention X₁X₂X₃ is selected from the group consisting of TIP, VIP, AIP, SVP, SQP, SAP, SGP, SIT, SIA, SIV and VQP.

According to a further preferred embodiment of the present invention X₄X₅X₆ is selected from the group consisting of SLE, ALE, QLE, DLE, NAE, NGE, NYE, NDE, NFE, NVE and NLD.

X₇(X₈)_(m), m being 1, is preferably selected from the group consisting of LT, TT, AT, IL, IQ, IA, IS, TL, LQ and LL.

According to a preferred embodiment of the present invention X₉ is selected from the group consisting of PPR, PP, P, APR, SPR, PAR, PVR, PTR, PNR, PPA, PPK, PPS and PPL.

According to a particularly preferred embodiment of the present invention the at least one peptide is selected from the group consisting of TIPWNLERIT, TIPWNLERITPPR, VIPWNLERIT, VIPWNLERITPPR, AIPWNLERIT, AIPWNLERITPPR, SVPWNLERIT, SVPWNLERITPPR, SQPWNLERIT, SQPWNLERITPPR, SAPWNLERIT, SAPWNLERITPPR, SGPWNLERITPPR, SGPWNLERIT, SIVWNLERIT, SITWNLERITPPR, SAPWNLERIT, SAPWNLERITPPR, SVPWNLERITPPR, SIVWNLERIT, SIPWSLERIT, SIPWSLERITPPR, SIPWALERIT, SIPWALERITPPR, SIPWQLERITPPR, SIPWQLERIT, SIPWDLERITPPR, SIPWDLERIT, SIPWNAERIT, SIPWNAERITPPR, SIPWNGERIT, SIPWNGERITPPR, SIPWNYERIT, SIPWNYERITPPR, SIPWNDERIT, SIPWNDERITPPR, SIPWNFERITPPR, SIPWNVERITPPR, SIPWNLDRITPPR, SIPWNFERIT, SIPWNVERIT, SIPWNLDRIT, SIPWNLERLT, SIPWNLERLTPPR, SIPWNLERTT, SIPWNLERTTPPR, SIPWNLERAT, SIPWNLERATPPR, SIPWNLERIL, SIPWNLERILPPR, SIPWNLERIQ, SIPWNLERIQPPR, SIPWNLERIA, SIPWNLERIAPPR, SIPWNLERISPPR, SIPWNLERIS, SIPWNLERIAPPR, SIPWNLERITSPR, SIPWNLERITPTR, SIPWNLERITPTR, SIPWNLERITPTR, SIPWNLERITPNR, SIPWNLERITPPA, SIPWNLERITPPK, SIPWNLERITPPS, SIPWNLERITPPL, VIPWNLERLT, VIPWNLERLTPPR, VIPWNLERIT, VIPWNLERTTPPR, VIPWNLERIL, VIPWNLERILPPR, VIPWNLERIQ, VIPWNLERIQPPR, SVPWNLERLT, SVPWNLERLTPPR, SVPWNLERTT, SVPWNLERTTPPR, SVPWNLERIL, SVPWNLERILPPR, SVPWNLERIQ, SVPWNLERIQPPR, SIPWSLERTTPPR, SQPWNLERLT, SQPWNLERLTPPR, SQPWNLERIL, SQPWNLERILPPR, SQPWNLERIQ, SQPWNLERIQPPR, SIPWSLERLT, SIPWSLERLTPPR, SIPWSLERTT, SIPWSLERIL, SIPWSLERILPPR, SIPWSLERIQ, SIPWSLERIQPPR, VQPWSLERTL, VQPWSLERTLPPR, SQPWSLERTL, SQPWSLERTLPPR, VQPWNLERLQ, VQPWNLERLQPPR, VQPWSLERLL, VQPWSLERLLPPR, SVPWSLERLT and SVPWSLERLTPPR.

According to a particularly preferred embodiment of the present invention the at least one peptide comprised in the vaccine of the present invention is selected from the group consisting of SIPWSLERIT, SIPWSLERITPPR, SIPWSLERTTPPR, VIPWNLERILPPR, SVPWNLERIQPPR, SIPWSLERTT, SIPWSLERLT, SIPWSLERLTPPR, SIPWSLERIQ, SIPWSLERIQPPR, VIPWNLERIL and SVPWNLERIQ.

TABLE A Amino acid residues Amino acid Three letter code One letter code alanine ala A arginine arg R asparagine asn N aspartic acid asp D cysteine cys C glutamic acid glu E glutamine gln Q glycine gly G histidine his H isoleucine ile I leucine leu L lysine lys K methionine met M phenylalanine phe F proline pro P serine ser S threonine thr T tryptophan trp W tyrosine tyr Y valine val V

According to a particularly preferred embodiment at least one peptide (SEQ ID No. 1) comprised in the vaccine of the present invention comprises at its N- and/or C-terminus at least one cysteine residue bound directly or via a spacer sequence thereto.

This cysteine residue may serve as a reactive group in order to bind the peptide to another molecule or a carrier. For instance, this group may be used to bind the peptide to a carrier protein. The cysteine residue can be bound directly to the peptides of the present invention or via a spacer sequence. The spacer sequence comprises preferably at least one, preferably at least two, more preferably at least three, even more preferably at least four, and optionally a maximum of ten, preferably a minimum of five small non-polar amino acid residues such as glycines.

According to a preferred embodiment of the present invention the carrier is selected from the group consisting of keyhole limpet haemocyanin (KLH), CRM (preferably CRM197), tetanus toxoid (TT), diphtheria toxin (DT), protein D or any other protein or peptide containing helper T-cell epitopes.

According to the present invention the peptide is coupled or fused to a pharmaceutically acceptable carrier, preferably KLH (Keyhole Limpet Hemocyanin), CRM, tetanus toxoid, albumin-binding protein, bovine serum albumin, a dendrimer, peptide linkers (or flanking regions) as well as the adjuvant substances described in Singh et al. (Singh et al., Nat. Biotech. 17, (1999): 1075-1081 (in particular those in Table 1 of that document)), and O'Hagan et al. (O'Hagan and Valiante, Nature Reviews, Drug Discovery 2 (9); (2003): 727-735 (in particular the endogenous immuno-potentiating compounds and delivery systems described therein)), or mixtures thereof. The conjugation chemistry (e.g. via heterobifunctional compounds such as GMBS and of course also others as described in “Bioconjugate Techniques”, Greg T. Hermanson) in this context can be selected from reactions known to the skilled man in the art.

Alternatively it is also possible to fuse the at least one peptide of the present invention to a protein carrier by methods known in the art. Such proteins comprise a peptide as described herein together with an unrelated immunogenic protein. Preferably the immunogenic protein is capable of eliciting a recall response. Examples of such proteins include tetanus, tuberculosis, hepatitis proteins and protein D, a surface protein of the gram-negative bacterium Haemophilus influenza B (WO 91/18926). Preferably a protein D derivative is used which comprises approximately the first third of the protein (e.g., the first N-terminal 100-110 amino acids) and which may be lipidated. Another carrier which may be used to provide fusion proteins may be the protein known as LYTA, or a portion thereof (preferably a C-terminal portion). LYTA is derived from Streptococcus pneumoniae, which synthesizes an N-acetyl-L-alanine amidase known as amidase LYTA (encoded by the LytA gene; Gene 43; (1986): 265-292). LYTA is an autolysin that specifically degrades certain bonds in the peptidoglycan backbone. Within a preferred embodiment, a repeat portion of LYTA may be incorporated into a fusion protein. A repeat portion is found in the C-terminal region starting at residue 178. A particularly preferred repeat portion incorporates residues 188-305.

According to a preferred embodiment of the present invention the peptide is formulated with an adjuvant, preferably adsorbed to aluminium hydroxide.

The vaccine according to the present invention may be formulated with an adjuvant, preferably a low soluble aluminum composition, in particular aluminum hydroxide. Of course, also adjuvants like MF59, aluminum phosphate, calcium phosphate, cytokines (e.g. IL-2, IL-12, GM-CSF), saponins (e.g. QS21), MDP derivatives, CpG oligonucleotides, LPS, MPL, polyphosphazenes, emulsions (e.g. Freund's, SAF), liposomes, virosomes, iscoms, cochleates, PLG microparticles, poloxamer particles, virus-like particles, heat-labile enterotoxin (LT), cholera toxin (CT), mutant toxins (e.g. LTK63 and LTR72), microparticles and/or polymerized liposomes may be used.

Suitable adjuvants are commercially available as, for example, AS01B, AS02A, AS15, AS-2 and derivatives thereof (GlaxoSmithKline, Philadelphia, Pa.); CWS, TDM, Leif, aluminum salts such as aluminum hydroxide gel (alum) or aluminum phosphate; salts of calcium, iron or zinc; an insoluble suspension of acylated tyrosine; acylated sugars; cationically or anionically derivatized polysaccharides; polyphosphazenes; biodegradable microspheres; monophosphoryl lipid A and quil A. Cytokines, such as GM-CSF or interleukin-2, -7 or -12 may also be used as adjuvants.

Preferred adjuvants for use in eliciting a predominantly Th1-type response include, for example, a combination of monophosphoryl lipid A, preferably 3-O-deacylated monophosphoryl lipid A (3D-MPL), optionally with an aluminum salt (see, for example, Ribi et al., Immunology and Immunopharmacology of Bacterial Endotoxins, Plenum Publ. Corp., NY, (1986): 407-419; GB 2122204B; GB 2220211; and U.S. Pat. No. 4,912,094). A preferred form of 3D-MPL is an emulsion having a small particle size less than 0.2 mm in diameter, and its method of manufacture is disclosed in WO 94/21292. Aqueous formulations comprising monophosphoryl lipid A and a surfactant have been described in WO 98/43670. Exemplified preferred adjuvants include AS01B (MPL and QS21 in a liposome formulation), 3D-MPL and QS21 in a liposome formulation, AS02A (MPL and QS21 and an oil-in-water emulsion), 3D-MPL and QS21 and an oil-in-water emulsion, and AS 15. MPL adjuvants are disclosed e.g. in U.S. Pat. No. 4,436,727; U.S. Pat. No. 4,877,611; U.S. Pat. No. 4,866,034 and U.S. Pat. No. 4,912,094.

CpG-containing oligonucleotides (in which the CpG dinucleotide is unmethylated) also induce a predominantly Th1 response. CpG is an abbreviation for cytosine-guanosine dinucleotide motifs present in DNA. Such oligonucleotides are well known and are described, for example, in WO 96/02555, WO 99/33488, U.S. Pat. No. 6,008,200 and U.S. Pat. No. 5,856,462. Immunostimulatory DNA sequences are also described, for example, by Sato et al., Science 273; (1996): 352. CpG when formulated into vaccines is generally administered in free solution together with free antigen (WO 96/02555; McCluskie and Davis, supra) or covalently conjugated to an antigen (WO 98/16247), or formulated with a carrier such as aluminium hydroxide ((Hepatitis surface antigen) Davis et al., supra; Brazolot-Millan et al., PNAS USA, 95(26), (1998): 15553-8). CpG is known in the art as being an adjuvant that can be administered by both systemic and mucosal routes (WO 96/02555, EP 0 468 520, Davis et al., J. Immunol, 160(2), (1998): 870-876; McCluskie and Davis, J. Immunol., 161(9), (1998): 4463-6).

Another preferred adjuvant is a saponin or saponin mimetics or derivatives, preferably QS21 (Aquila Biopharmaceuticals Inc.), which may be used alone or in combination with other adjuvants. For example, an enhanced system involves the combination of a monophosphoryl lipid A and saponin derivative, such as the combination of QS21 and 3D-MPL as described in WO 94/00153, or a less reactogenic composition where the QS21 is quenched with cholesterol as described in WO 96/33739. Other preferred formulations comprise an oil-in-water emulsion and tocopherol. A particularly potent adjuvant formulation involving QS21, 3D-MPL and tocopherol in an oil-in-water emulsion is described in WO 95/17210. Additional saponin adjuvants of use in the present invention include QS7 (described in WO 96/33739 and WO 96/11711) and QS17 (described in U.S. Pat. No. 5,057,540 and EP 0 362 279 B1).

Other preferred adjuvants include Montanide ISA 720 (Seppic, France), SAF (Chiron, Calif., United States), ISCOMS (CSL), MF-59 (Chiron), the SBAS series of adjuvants (e.g., SBAS-2, AS2′, AS2, SBAS-4, or SBAS6, available from GlaxoSmithKline), Detox (Corixa), RC-529 (Corixa, Hamilton, MT) and other amino-alkyl glucosaminide 4-phosphates (AGPs). Further example adjuvants include synthetic MPL and adjuvants based on Shiga toxin B subunit (see WO 2005/112991). It is particularly preferred to use aluminium hydroxide as adjuvant.

The vaccine of the present invention may be administered subcutaneously, intramuscularly, intradermally, intravenously (see e.g. “Handbook of Pharmaceutical Manufacturing Formulations”, Sarfaraz Niazi, CRC Press Inc, 2004). Depending on the route of administration, the medicament may comprise respective carriers, adjuvants, and/or excipients.

A vaccine which comprises a peptide of the present invention and the pharmaceutically acceptable carrier may be administered by any suitable mode of application, e.g. intradermally (i.d.), intraperitoneally (i.p.), intramuscularly (i.m.), intranasally, orally, subcutaneously (s.c.), etc. and in any suitable delivery device (O'Hagan et al., Nature Reviews, Drug Discovery 2 (9), (2003), 727-735). The peptides of the present invention are preferably formulated for intradermal, subcutaneous or intramuscular administration. Means and methods for obtaining respective formulations are known to the person skilled in the art (see e.g. “Handbook of Pharmaceutical Manufacturing Formulations”, Sarfaraz Niazi, CRC Press Inc, 2004).

According to a preferred embodiment of the present invention the vaccine is used in the treatment and/or prevention of disorders caused by hyperlipidemia, hypercholesterolemia and/or atherosclerosis, preferably cardiovascular diseases, stroke or peripheral vascular diseases in particular in mammals, preferably in humans.

As outlined, the peptides of the present invention are able to induce the formation of antibodies which are able to bind specifically PCSK9. The interaction of the antibodies with PCSK9 leads to the increase of low density lipoprotein receptor in liver hepatocytes in vivo, increased plasma cholesterol uptake and subsequent reduction of the plasma LDL cholesterol levels and thus the overall cholesterol levels.

The disease associated with atherosclerosis is preferably selected from the group consisting of peripheral arterial occlusive disease, coronary heart disease, apoplectic cerebral insultus and stroke.

The terms “diseases associated with hyperlipidemia, hypercholesterolemia and/or atherosclerosis” and “disorders caused by hyperlipidemia, hypercholesterolemia and/or atherosclerosis” refer to diseases which are a consequence of hyperlipidemia, hypercholesterolemia and atherosclerosis. These diseases include among others peripheral arterial occlusive disease, coronary heart disease and apoplectic cerebral insultus (see e.g. Steinberg, D. J Lipid Res 46(2005): 179-190 and Steinberg, D. J Lipid Res 47(2006): 1339-1351).

According to a preferred embodiment of the present invention the peptides of the present invention are administered to a mammal or an individual in an amount of 0.1 ng to 10 mg, preferably of 0.5 to 500 μg, more preferably 1 to 100 μg, per immunization. In a preferred embodiment these amounts refer to all peptides (if more than one peptide is used in the vaccine) present in the vaccine. In another preferred embodiment these amounts refer to each single fragment present in the vaccine. It is of course possible to provide a vaccine in which the peptides are present in different or equal amounts. However, the peptide of the present invention may alternatively be administered to a mammal or an individual in an amount of 0.1 ng to 10 mg, preferably 10 ng to 1 mg, in particular 100 ng to 300 μg/kg body weight.

The amount of peptides that may be combined with the carrier materials to produce a single dosage form will vary depending upon the host treated and the particular mode of administration. The dose of the vaccine may vary according to factors such as the disease state, age, sex and weight of the mammal or individual, and the ability of antibody to elicit a desired response in the individual. Dosage regime may be adjusted to provide the optimum therapeutic response. For example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation. The dose of the vaccine may also be varied to provide optimum preventative dose response depending upon the circumstances. For instance, the peptides and vaccine of the present invention may be administered to an individual at intervals of several days, one or two weeks or even months or years depending always on the level of antibodies directed to PCSK9.

In a preferred embodiment of the present invention the peptide/vaccine is applied between 2 and 10, preferably between 2 and 7, even more preferably up to 5 and most preferably up to 4 times. This number of immunizations may lead to a basic immunisation. In a particularly preferred embodiment the time interval between the subsequent vaccinations is chosen to be between 2 weeks and 5 years, preferably between 1 month and up to 3 years, more preferably between 2 months and 1.5 years. An exemplified vaccination schedule may comprise 3 to 4 initial vaccinations over a period of 6 to 8 weeks and up to 6 months. Thereafter the vaccination may be repeated every two to ten years. The repeated administration of the peptide/vaccine of the present invention may maximize the final effect of a therapeutic vaccination.

The vaccine of the present invention may also comprise antigens derived from other proteins which are also involved in the regulation of the LDL and/or HDL levels within a human body. For instance, the PCSK9 fragments of the present invention may be combined with epitopes derived from human CETP protein. The vaccine of the present invention may also comprise antigens derived from a different epitope of the PCSK9 protein.

Typically, the vaccine contains the peptides of the present invention in an amount of 0.5 to 500 μg, preferably 1 to 100 μg and alternatively from 0.1 ng to 10 mg, preferably 10 ng to 1 mg, in particular 100 ng to 100 μg, or, alternatively, e.g. 100 fmol to 10 μmol, preferably 10 pmol to 1 μmol, in particular 100 pmol to 100 nmol. Typically, the vaccine may also contain auxiliary substances, e.g. buffers, stabilizers etc.

Yet another aspect of the present invention relates to a method for treating an individual suffering or at risk to suffer from atherosclerosis or a disease associated with atherosclerosis in the course of which a peptide or vaccine according to the present invention is administered to said individual.

Next to the vaccine of the present invention, the individual to be treated may receive also other active ingredients known to influence the LDL and/or HDL levels in humans and mammals such as statins, fibrates, nicotinic acid, cholesterol uptake inhibitor (e.g. ezetimibe), ApoA1 Milano, delipidated HDL, plant sterols. It is particularly preferred to administers to an individual the vaccine of the present invention together (i.e. at the same time, consecutively etc.) with statins. The vaccine of the present invention can also be combined with methods like LDL apheresis. LDL apheresis is a form of apheresis to eliminate the cholesterol-containing particle low-density lipoprotein (LDL) from the bloodstream. Typically LDL apheresis works by leading venous blood through a column coated with antibodies to apolipoprotein B (the main protein of LDL particles), dextran sulfate or polyacrylate, or by precipitating LDL with heparin at low pH. Respective methods are known to a person skilled in the art.

The term “preventing”, as used herein, covers measures not only to prevent the occurrence of disease, such as risk factor reduction, but also to arrest its progress and reduce its consequences once established.

As used herein, the term “treatment” or grammatical equivalents encompasses the improvement and/or reversal of the symptoms of disease. A compound which causes an improvement in any parameter associated with disease when used in the screening methods of the instant invention may thereby be identified as a therapeutic compound. The term “treatment” refers to both therapeutic treatment and prophylactic or preventative measures. For example, those who may benefit from treatment with compositions and methods of the present invention include those already with a disease and/or disorder as well as those in which a disease and/or disorder is to be prevented (e.g., using a prophylactic treatment of the present invention).

Another aspect of the present invention relates to a peptide consisting of an amino acid sequence X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m)(X₉)_(n) (SEQ ID No. 1) as defined above.

The present invention is further illustrated by the following embodiments, figures and example, however, without being restricted thereto.

EMBODIMENTS

1. Vaccine comprising at least one peptide consisting of 9 to 25 amino acid residues having the amino acid sequence

(SEQ ID No. 1) X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m)(X₉)_(n), wherein

X₁ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of serine, threonine, valine and alanine,

X₂ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group of isoleucine, valine, glycine, glutamine and alanine, more preferably isoleucine, valine, glutamine and alanine.

X₃ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, threonine, alanine and valine, more preferably proline,

X₄ is an amino acid residue selected from the group consisting of asparagine, serine, alanine, glutamine and aspartic acid,

X₅ is an amino acid residue selected from the group consisting of leucine, glycine, alanine, tyrosine, aspartic acid, phenylalanine and valine, preferably leucine,

X₆ is an amino acid residue selected from the group of hydrophilic, negatively charged amino acid residue, preferably an amino acid residue selected from the group consisting of glutamic acid and aspartic acid,

X₇ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of isoleucine, leucine, alanine and threonine,

X₈ is an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of threonine, leucine, glutamine, alanine and serine,

X₉ is X₁₀X₁₁X₁₂ or a C-terminal truncated fragment thereof consisting of 1 or 2 amino acid residues,

X₁₀ is any amino acid residue, preferably an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, alanine and serine,

X₁₁ is any amino acid residue, preferably an amino acid residue selected from the group of uncharged amino acid residues, preferably selected from the group consisting of proline, alanine, valine, threonine and asparagine,

X₁₂ is any amino acid residue, preferably an amino acid residue selected from the group consisting of arginine, alanine, lysine, serine, and leucine,

m is 0 or 1,

n is 0 or 1, and

SEQ ID No. 1 is not SIPWNLERITPPR or a C-terminal truncated fragment thereof,

wherein said at least one peptide is coupled or fused to a pharmaceutically acceptable carrier.

2. Vaccine according to embodiment 1, wherein X₁ is valine, serine or alanine, preferably valine.

3. Vaccine according to embodiment 1 or 2, wherein X₂ is valine, isoleucine or glutamine, preferably valine.

4. Vaccine according to any one of embodiments 1 to 3, wherein X₃ is proline, threonine, alanine or valine.

5. Vaccine according to any one of embodiments 1 to 4, wherein X₄ is serine or asparagine, preferably serine.

6. Vaccine according to any one of embodiments 1 to 5, wherein X₆ is glutamic acid.

7. Vaccine according to any one of embodiments 1 to 6, wherein X₇ is leucine, isoleucine or threonine, preferably threonine.

8. Vaccine according to any one of embodiments 1 to 7, wherein X₈ is glutamine, threonine or leucine.

9. Vaccine according to any one of embodiments 1 to 8, wherein X₁X₂X₃ is selected from the group consisting of TIP, VIP, AIP, SVP, SQP, SAP, SGP, SIT, SIA, SIV and VQP.

10. Vaccine according to any one of embodiments 1 to 9, wherein X₄X₅X₆ is selected from the group consisting of SLE, ALE, QLE, DLE, NAE, NGE, NYE, NDE, NFE, NVE and NLD.

11. Vaccine according to any one of embodiments 1 to 10, wherein X₇(X₈)_(m), m being 1, is selected from the group consisting of LT, TT, AT, IL, IQ, IA, IS, TL, LQ and LL.

12. Vaccine according to any one of embodiments 1 to 11, wherein X₉ is selected from the group consisting of PPR, PP, P, APR, SPR, PAR, PVR, PTR, PNR, PPA, PPK, PPS and PPL.

13. Vaccine according to any one of embodiments 1 to 12, wherein the at least one peptide is selected from the group consisting of TIPWNLERIT, TIPWNLERITPPR, VIPWNLERIT, VIPWNLERITPPR, AIPWNLERIT, AIPWNLERITPPR, SVPWNLERIT, SVPWNLERITPPR, SQPWNLERIT, SQPWNLERITPPR, SAPWNLERIT, SAPWNLERITPPR, SGPWNLERITPPR, SGPWNLERIT, SITWNLERIT, SITWNLERITPPR, SIAPWNLERIT, SIAWNLERITPPR, SIVWNLERITPPR, SIVWNLERIT, SIPWSLERIT, SIPWSLERITPPR, SIPWALERIT, SIPWALERITPPR, SIPWQLERITPPR, SIPWQLERIT, SIPWDLERITPPR, SIPWDLERIT, SIPWNAERIT, SIPWNAERITPPR, SIPWNGERIT, SIPWNGERITPPR, SIPWNYERIT, SIPWNYERITPPR, SIPWNDERIT, SIPWNDERITPPR, SIPWNFERITPPR, SIPWNVERITPPR, SIPWNLDRITPPR, SIPWNFERIT, SIPWNVERIT, SIPWNLDRIT, SIPWNLERLT, SIPWNLERLTPPR, SIPWNLERTT, SIPWNLERTTPPR, SIPWNLERAT, SIPWNLERATPPR, SIPWNLERIL, SIPWNLERLTPPR, SIPWNLERIQ, SIPWNLERIQPPR, SIPWNLERIA, SIPWNLERIAPPR, SIPWNLERISPPR, SIPWNLERIS, SIPWNLERITAPR, SIPWNLERITSPR, SIPWNLERITPAR, SIPWNLERITPVR, SIPWNLERITPTR, SIPWNLERITPNR, SIPWNLERITPPA, SIPWNLERITPPK, SIPWNLERITPPS, SIPWNLERITPPL, VIPWNLERLT, VIPWNLERILPPR, VIPWNLERTT, VIPWNLERIQPPR, VIPWNLERIL, VIPWNLERILPPR, VIPWNLERIQ, VIPWNLERIQPPR, SVPWNLERLT, SVPWNLERILPPR, SVPWNLERTT, SVPWNLERILPPR, SVPWNLERIL, SVPWNLERILPPR, SVPWNLERIQ, SVPWNLERIQPPR, SIPWSLERTTPPR, SQPWNLERLT, SQPWNLERILPPR, SQPWNLERIL, SQPWNLERILPPR, SQPWNLERIQ, SQPWNLERIQPPR, SIPWSLERLT, SIPWSLERLTPPR, SIPWSLERTT, SIPWSLERIL, SIPWSLERILPPR, SIPWSLERIQ, SIPWSLERIQPPR, VQPWSLERTL, VQPWSLERTLPPR, SQPWSLERTL, SQPWSLERTLPPR, VQPWNLERLQ, VQPWNLERLQPPR, VQPWSLERLL, VQPWSLERLLPPR, SVPWSLERLT and SVPWSLERLTPPR.

14. Vaccine according to any one of embodiments 1 to 13, wherein the at least one peptide is selected from the group consisting of SIPWSLERIT, SIPWSLERITPPR, SIPWSLERTTPPR, VIPWNLERILPPR, SVPWNLERIQPPR, SIPWSLERTT, SIPWSLERLT, SIPWSLERLTPPR, SIPWSLERIQ, SIPWSLERIQPPR, VIPWNLERIL and SVPWNLERIQ.

15. Vaccine according to any one of embodiments 1 to 14, wherein the at least one peptide comprises at its N- and/or C-terminus at least one cysteine residue bound directly or via a spacer sequence thereto.

16. Vaccine according to any one of embodiments 1 to 15, wherein the pharmaceutically acceptable carrier is a protein carrier.

17. Vaccine according to embodiment 16, wherein the protein carrier is selected from the group consisting of keyhole limpet haemocyanin (KLH), tetanus toxoid (TT), protein D or diphtheria toxin (DT), preferably a mutated diphtheria toxin, more preferably CRM197.

18. Vaccine according to any one of embodiments 1 to 17, wherein the compound is formulated with an adjuvant, preferably adsorbed to Alhydrogel.

19. Vaccine according to any one of embodiments 1 to 18 to be used in a method for treating and/or preventing disorders caused by hyperlipidemia, hypercholesterolemia and/or atherosclerosis, preferably cardiovascular diseases, stroke or peripheral vascular diseases.

20. Peptide consisting of an amino acid sequence X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m)(X₉)_(n) (SEQ ID No. 1) as defined in any one of embodiments 1 to 15.

FIG. 1 Binding ELISA

FIG. 1 shows detection of PCSK9 mimotopes sequences by mouse sera containing polyclonal antibodies specific for human PCSK9 aa 153-162 or aa 153-165

A) Mimotopes containing single exchanges

B) Mimotopes containing multiple exchanges

The graphs display median titers from all mimotopes compared to the irrelevant negative control. As a positive control the original human PCSK9 sequence is included: aa 153-162 or aa 153-165. Mimotopes with values over 1:50.000 are considered as good candidates.

FIG. 2 Competition ELISA

FIG. 2 shows the ability of PCSK9 mimotopes to compete with the original PCSK9 sequence (aa 153-162 or aa 153-165) for binding polyclonal antibodies in mouse sera raised specifically against the latter.

All mimotopes are compared to the negative group (0% competition by an irrelevant peptide). As a positive control for each competition ELISA the original PCSK9 sequences were used (aa 153-162 or aa 153-165).

A) Mimotopes containing single exchanges

B) Mimotopes containing multiple exchanges

The graphs display the ability (in percent) of the mimotopes to compete with the original PCSK9 sequence (aa 153-162 or aa 153-165) for binding polyclonal antibodies raised against the latter.

Mimotopes with competition ability over 20% are considered as good candidates.

FIG. 3 Protein ELISA

FIG. 3 shows comparison of the median titers (n=5 mice/group) against human PCSK9 protein induced by the indicated sequences. The data reveal the ability of the mimotopes to induce antibodies cross-reacting with human PCSK9 protein. Antibodies raised by irrelevant peptide do not recognize the protein.

FIG. 4 Total Cholesterol (% compared to control group)

FIG. 4 shows comparison of the mean (n=5 mice/group) total cholesterol levels of mice immunized with mimotopes in comparison to a control group immunized with irrelevant peptide. The data reveal the ability of the mimotopes to substantially lower the levels of total cholesterol in mice up to approximately 30%.

FIG. 5 Total cholesterol (TC) levels upon vaccination

FIG. 5 shows total cholesterol (TC) levels upon vaccination with original PCSK9 sequence SIPWNLERIT and novel sequence SIPWSLERIT (direct comparison).

FIG. 6 Total cholesterol (TC) levels upon immunization

FIG. 6 shows total cholesterol (TC) levels upon immunization with vaccines containing the novel sequences SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ.

EXAMPLES

Materials and Methods

Vaccine:

The peptides were conjugated via the heterobifunctional linker GMBS (4-Maleimidobutyric acid N-hydroxysuccinimide ester) to KLH (Keyhole Limpet Hemocyanin).

Animal Experiments:

5 Balb/c mice were subcutaneously immunized. Mice had access to food and water ad libitum and were kept under a 12 h light/dark cycle. The age of mice at the beginning of experiments was 8 to 10 weeks.

Mice were injected four times in 2 week intervals with 15 μg of net peptide coupled to KLH and adsorbed to Alhydrogel as adjuvant in a volume of 1 ml in total.

Blood was taken approximately 2 weeks after the final injection.

Competition ELISA:

20 μg of each indicated peptide was incubated with sera from mice injected with original PCSK9 sequence (aa 153-162 or aa 153-165: SEQ ID No. 2). Sera were then incubated on ELISA plates coated with the original PCSK9 sequence (aa 153-162 or aa 153-165: SEQ ID No. 2). Detection was performed with anti-mouse IgG antibodies, ABTS was used as a chromogenic substrate and optical density (OD) was measured at 405 nm.

Mimotopes diminishing >20% subsequent binding of the polyclonal antibodies from the sera to the original human PCSK9 epitope (aa 153-162 or 153-165: SEQ ID No. 3) coated on the ELISA plates were considered as competing mimotopes and as good candidates.

Binding ELISA:

Mimotopes were coated on ELISA plates at a concentration of 1 μmol/mL. After blocking unspecific binding (1% BSA in PBS) appropriate dilutions of sera from mice injected with the original human PCSK9 sequence aa 153-162 or aa 153-165 (SEQ ID No.3) were added and incubated for approximately 1 hour. Subsequently, detection with anti-mouse IgG antibodies was performed. ABTS was used as substrate. OD measurements were performed at 405 nm and titers were defined as the dilution of the serum where 50% of the ODmax is reached.

Protein ELISA:

To determine the immunogenicity of the vaccines, ELISA plates were coated with recombinantly expressed human PCSK9 protein. Unspecific binding was blocked by incubation with blocking buffer (1% BSA in PBS). Appropriate serum dilutions were added to the wells, serially diluted 1:2 fold and incubated for approximately 1 hour. Bound antibodies were detected by incubation with anti-mouse IgG antibod, ABTS was added as substrate and the OD at 405 nm was measured. As negative control sera from the control group injected with an irrelevant peptide were analyzed. The titers were defined as the dilution of the serum where 50% of the ODmax in the assay is reached.

Total Cholesterol Assay:

Total cholesterol was measured with the LabAssay™ Cholesterol Kit (Wako).

Results

Example 1

List of sequences and median antibody titers against original human PCSK9 sequence (See FIG. 1A and FIG. 1B) and competition capacity (in percent) of the mimotopes, compared to the negative control group (See FIG. 2A and FIG. 2B). In order to facilitate coupling of the peptides to KLH the peptides may comprise a cysteine residue as a linker at the C-terminus.

% Compe- tition Median compared Titer to the Binding related ELISA control Seq ID Sequence (ODmax/2) group 1 X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m) (X₉)_(n) 2 SIPWNLERITPPR 3 ERTKSDPGAQHREF 0 (negative control) 4 ITELSRWPNI 0 (negative control) 5 TIPWNLERIT 198,000 52 6 VIPWNLERIT 152,000 51 7 AIPWNLERIT 199,000 83 8 SVPWNLERIT 197,000 62 9 SQPWNLERIT 149,000 30 10 SAPWNLERIT 131,000 76 11 SGPWNLERITPPR 81,000 54 12 SITWNLERIT 124,000 62 13 SIAWNLERIT 147,000 78 14 SIVWNLERITPPR 146,000 78 15 SIPFNLERIT 42,000 15 16 SIPANLERIT 22,000 8 17 SIPGNLERIT 21,000 0 18 SIPHNLERIT 23,000 0 19 SIPDNLERIT 23,000 3 20 SIPSNLERIT 22,000 7 21 SIPWSLERIT 147,000 73 22 SIPWALERIT 157,000 75 23 SIPWQLERITPPR 224,000 79 24 SIPWDLERITPPR 231,000 74 25 SIPWNAERIT 156,000 73 26 SIPWNGERIT 56,000 52 27 SIPWNYERIT 115,000 76 28 SIPWNDERIT 131,000 71 29 SIPWNFERITPPR 186,000 79 30 SIPWNVERITPPR 197,000 78 31 SIPWNLARIT 34,000 13 32 SIPWNLDRITPPR 151,000 53 33 SIPWNLEKIT 59,000 19 34 SIPWNLEAIT 54,000 15 35 SIPWNLEDIT 48,000 13 36 SIPWNLERLT 192,000 76 37 SIPWNLERTT 177,000 73 38 SIPWNLERAT 149,000 77 39 SIPWNLERIL 168,000 56 40 SIPWNLERIQ 181,000 64 41 SIPWNLERIA 189,000 80 42 SIPWNLERISPPR 219,000 79 43 SIPWNLERITAPR 226,000 70 44 SIPWNLERITSPR 153,000 68 45 SIPWNLERITPAR 184,000 74 46 SIPWNLERITPVR 265,000 75 47 SIPWNLERITPTR 155,000 73 48 SIPWNLERITPNR 186,000 70 49 SIPWNLERITPPA 163,000 65 50 SIPWNLERITPPK 158,000 66 51 SIPWNLERITPPS 149,000 66 52 SIPWNLERITPPL 139,000 66 53 VIPWNLERLT 191,000 54 54 VIPWNLERTT 162,000 69 55 VIPWNLERIL 173,000 49 56 VIPWNLERIQ 166,000 47 57 SVPWNLERLT 154,000 57 58 SVPWNLERTT 116,000 73 59 SVPWNLERIL 188,000 59 60 SVPWNLERIQ 222,000 61 61 SQPWNLERLT 200,000 69 62 SVPWNLERIL 196,000 69 63 SQPWNLERIQ 167,000 66 64 SIPWSLERLT 164,000 46 65 SIPWSLERTT 147,000 64 66 SIPWSLERIL 199,000 46 67 SIPWSLERIQ 223,000 44 68 VQPWSLERTL 95,000 48 69 SQPWSLERTL 98,000 53 70 SVPWNLEKLT 47,000 11 71 VQPWNLERLQ 184,000 72 72 VQPWSLERLL 166,000 66 75 SVPWSLERLT 251,000 74

Example 2 Unexpected Effect of the Peptides According to the Present Invention

In a further experiment, the functionality of the antibodies raised upon immunization with the peptide vaccines according to the present invention is investigated. In the present experiment, the highly significant functionality of the antibodies raised upon immunization with vaccines containing the novel sequences (SEQ ID No.21 SIPWSLERIT, SEQ ID No. 55 VIPWNLERIL and SEQ ID No. 60 SVPWNLERIQ) is demonstrated in comparison to the antibodies raised upon vaccination with vaccines containing the original PCSK9 sequence (SIPWNLERIT) and a negative control sequence-all coupled to the same carrier KLH (FIG. 5 and FIG. 6).

For this purpose mice have been immunized with HPLC purified peptides coupled to KLH and formulated with an adjuvant (Alum) as vaccines (Sequence-KLH/Alum). In the first experiment, a direct comparison between the original PCSK9 sequence and the novel sequence SIPWSLERIT has been performed. Here, mice have been immunized with irrelevant peptide vaccine (irrelevant peptide-KLH/Alum) as a negative control group, original PCSK9 sequence vaccine (SIPWNLERIT-KLH/Alum) and the novel sequence vaccine (SIPWSLERIT-KLH/Alum). The latter group (SIPWSLERIT-KLH/Alum) has been used not only to compare its functionality of the induced antibodies to the functionality of the antibodies generated using the original PCSK9 sequence vaccine (SIPWNLERIT-KLH/Alum), but also as a bridging group between different experiments. As it is shown, both vaccines—the original PCSK9 sequence vaccine (SIPWNLERIT-KLH/Alum) and the novel sequence vaccine (SIPWSLERIT-KLH/Alum) are able to strongly reduce the levels of total cholesterol in comparison to the negative control group (FIGS. 5a and 5b ). However interestingly, upon vaccination with the novel sequence vaccine (SIPWSLERIT-KLH/Alum), mice show a significant reduction of total cholesterol, compared not only to the negative control group but in fact, compared also to the group injected with vaccines containing the original PCSK9 sequence SIPWNLERIT (FIG. 5a and FIG. 5b ).

Subsequently, a second experiment has been performed wherein mice have been immunized with irrelevant peptide as a negative control group and all the three novel sequences SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ, all coupled to KLH and formulated as vaccines. As it has been already mentioned above, the mice immunized with the novel sequence (SIPWSLERIT-KLH/Alum) have been used as a bridging group between the experiments. In fact, the bridging group injected with the novel sequence (SIPWSLERIT-KLH/Alum) is behaving in a similar way in both experiments (FIGS. 5a, 5b, 6a and 6b ) and most importantly, all three groups immunized with vaccines containing one of the sequences SIPWSLERIT, VIPWNLERIL or SVPWNLERIQ behave in a very similar way in terms of reduction of plasma total cholesterol levels (FIG. 6a and FIG. 6b ).

Thus, the present data confirm the significant efficiency of the vaccines according to the present invention, especially the peptide vaccines containing the sequences SEQ ID No.21 SIPWSLERIT, SEQ ID No. 55 VIPWNLERIL and SEQ ID No. 60 SVPWNLERIQ, to induce functional antibodies that are able not only strongly to decrease the levels of plasma TC compared to the irrelevant negative control, but also to significantly reduce the total cholesterol levels in comparison to a vaccine containing the original PCSK9 sequence (SIPWNLERIT-KLH/Alum).

FIG. 5a shows the plasma mean values in mg/dl upon immunization with vaccine containing the novel sequence SIPWSLERIT, compared to immunization with vaccine containing the original PCSK9 sequence SIPWNLERIT and to the irrelevant (negative) control group (SEQ ID No. 2 ERTKSDPGAQHREF). The highly significant reduction of the TC levels in the group immunized with vaccine containing the novel sequence SIPWSLERIT, compared on one side to vaccine containing the original PCSK9 sequence SIPWNLERIT and on the other side to the negative control group, is evident from this figure. FIG. 5b provides the % decrease of TC of the groups, compared to the irrelevant (negative) control group. Specific attention should be given to the ˜20% reduction of TC upon vaccination with the original PCSK9 sequence (SIPWNLERIT-KLH/Alum), compared to the irrelevant negative control and the very strong up to 35-40% reduction in TC levels upon vaccination with the novel sequence (SIPWSLERIT-KLH/Alum).

FIG. 6a shows the plasma mean values in mg/dl upon immunization with vaccines containing the novel sequences SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ, compared to the irrelevant (negative) control group (SEQ ID No. 2 ERTKSDPGAQHREF). The highly significant reduction of the TC levels in all three groups immunized with the novel sequences in comparison to the negative control group, is evident from this figure. FIG. 6b provides the % decrease of TC of the groups injected with SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ, compared to the irrelevant (negative) control group. Specific attention should be given to the significantly strong—up to 40% reduction of TC upon vaccination with all three novel sequences SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ. In fact, the group immunized with vaccine containing the novel sequence SIPWSLERIT (bridging group between experiments) has behaved in a similar way in both experiments (see FIGS. 5a and 5b ), confirming the significantly higher functionality of the antibodies generated upon immunizations with vaccines containing the novel sequences SIPWSLERIT, VIPWNLERIL and SVPWNLERIQ, in comparison to vaccines containing the original PCSK9 sequence SIPWNLERIT.

From these data it is evident that the vaccines according to the present invention, especially the peptide vaccines comprising the sequences SEQ ID No. 21 SIPWSLERIT, SEQ ID No. 55 VIPWNLERIL and SEQ ID No. 60 SVPWNLERIQ show an unexpected and surprisingly advantageous effect compared to the vaccines presented in the prior art. 

The invention claimed is:
 1. A vaccine, comprising a peptide consisting of 10 to 13 amino acid residues and comprising an amino acid sequence selected from the group consisting of SIPWSLERIT (SEQ ID No. 21), VIPWNLERIL (SEQ ID No. 55), and SVPWNLERIQ (SEQ ID No. 60), wherein the peptide is coupled or fused to a pharmaceutically acceptable carrier.
 2. The vaccine according to claim 1, wherein the peptide is selected from the group consisting of SIPWSLERIT (SEQ ID NO:21), SIPWSLERITPPR (SEQ ID NO:87), VIPWNLERIL (SEQ ID NO:55), VIPWNLERILPPR (SEQ ID NO:99), SVPWNLERIQ (SEQ ID NO:60), and SVPWNLERIQPPR (SEQ ID NO:106).
 3. The vaccine according to claim 1, wherein the peptide comprises at its N- and/or C-terminus, a cysteine residue bound directly or via a spacer sequence thereto.
 4. The vaccine according to claim 1, wherein the pharmaceutically acceptable carrier is a protein carrier.
 5. The vaccine according to claim 4, wherein the protein carrier is selected from the group consisting of keyhole limpet haemocyanin (KLH), tetanus toxoid (TT), and protein D or diphtheria toxin (DT).
 6. The vaccine according to claim 1, wherein the compound is formulated with an adjuvant.
 7. A method comprising treating a disorder caused by hyperlipidemia, hypercholesterolemia and/or atherosclerosis, by administering the vaccine according to claim 1 to an individual in need thereof.
 8. A peptide consisting of an amino acid sequence (SEQ ID No. 1) X₁X₂X₃WX₄X₅X₆RX₇(X₈)_(m)(X₉)_(n),

wherein X₁ is serine or valine, X₂ is isoleucine or valine, X₃ is proline, X₄ is asparagine or serine, X₅ is leucine, X₆ is glutamic acid, X₇ is isoleucine, X₈ is threonine, leucine, or glutamine, X₉ is X₁₀X₁₁X₁₂ or a C-terminal truncated fragment thereof consisting of 1 or 2 amino acid residues, X₁₀ is proline, alanine, or serine, X₁₁ is proline, alanine, valine, threonine, or asparagine, X₁₂ is arginine, alanine, lysine, serine, or leucine, provided that if X₁ is serine, then X₂, X₄, and X₈ are either isoleucine, serine, and threonine, or valine, asparagine, and glutamine, and if X₁ is valine, then X₂, X₄, and X₈ are isoleucine, serine, and leucine, in is 0 or 1, n is 0 or
 1. 9. The peptide according to claim 8, wherein X₉ is proline-proline-arginine.
 10. The peptide according to claim 8, selected from the group consisting of SIPWSLERIT (SEQ ID No. 21), SIPWSLERITPPR (SEQ ID No. 87), VIPWNLERIL (SEQ ID No. 55), VIPWNLERILPPR (SEQ ID No. 99), SVPWNLERIQ (SEQ ID No. 60), and SVPWNLERIQPPR (SEQ ID No. 106).
 11. The peptide according to claim 8, selected from the group consisting of SIPWSLERIT (SEQ ID No. 21), VIPWNLERIL (SEQ ID No. 55), and SVPWNLERIQ (SEQ ID No. 60). 